Since I was born and brought up in a rural town, I have a great interest in nature. Using the chance of studying abroad in my second year at college, I decided to go to Canada just because I wanted to see the beautiful phenomena there. So after I finished the study program, I went to Yellowknife in the Northwest Territories.
I clearly remember the sixth night in Yellowknife. Suddenly my host mother came to my room around 8 p．m. and told me to change clothes and go outside quickly carrying her camera.
The northern lights were flickering (闪烁) in the sky! I was shocked and just stood there with my mouth open. I forgot to take pictures of the mysterious lights.
Since that night, whenever it was sunny, I went outside at night and looked at the sky. It was so cold that I lost all feeling in my hands and feet.
As I took pictures of the northern lights, I came to find a characteristic movement of the lights. They first appear in the north part of the sky and then they gradually come down to the south part of the sky. After that, suddenly, they come in the middle of the north and south only for a while, which is the time when the best northern lights can be seen. Since it is only a few seconds for the northern lights to come down to the middle of the sky, it is very hard to get good pictures.
The stronger the sun acts, the better and stronger the northern lights flicker in the sky. That's because they come about from the collisions (碰撞) between atmospheric gases and the solar wind. Much more solar wind comes to the earth when the sun is active, which leads to the best northern lights. And the colors of the northern lights depend on the height of the collisions and the kinds of gases.
语篇解读：本文是一篇记叙文。作者出生在乡下，对大自然有浓厚的兴趣。他利用大二出国学习的机会去了加拿大，因为他想观看那里美丽的景象。
1．Why did the host mother ask the author to go out?
A．She wanted to take a picture of him.
B．She wanted to take a walk with him.
C．She wanted to tell him something important.
D．She wanted him to see the northern lights.
解析：选D 推理判断题。根据房东妈妈让作者立刻到外面去并带上照相机以及下文对northern lights的描写可知，房东妈妈叫作者到外面去的目的是观看北极光。
2．The author forgot to take pictures after going out because .
A．the host mother didn't remind him to take the camera
B．he was shocked by the wonderful sight
C．the lights flickering in the sky disappeared too soon
D．he lost all feeling in his hands and feet
解析：选B 细节理解题。根据第三段中的“I was shocked and just stood there with my mouth open”可知，作者为观看到的景象所震惊，所以忘了照相。
3．When is the best time to see the northern lights?
A．When they appear in the north part of the sky.
B．When they come down to the south part of the sky.
C．When they are between the north and south.
D．When they rise in the east part of the sky.
解析：选C 细节理解题。从第五段中的第三句话可知，当北极光位于北部和南部中间时是最佳观看时间，故选C项。
4．What does the last paragraph mainly tell us?
A．Ways to take good pictures.
B．The relationship between the sun and the northern lights.
C．The colors of the northern lights.
D．The time of the best northern lights.
解析：选B 段落大意题。根据最后一段的内容，尤其是第一句“The stronger the sun acts, the better and stronger the northern lights flicker in the sky”可知，本段主要介绍了太阳和北极光的关系。
